1. Field of the Invention
Apparatuses and methods consistent with the present invention relate to a scheduled recording method, and more particularly, to a scheduled-recording method that schedules recording of content that is copy-protected under digital rights management.
2. Description of the Related Art
In recent years, home networks have received more and more attention from the public. A home network is a network that comprises devices for reproducing content and devices for managing the devices that reproduce content. Additionally, home networks provide digital rights management for content reproduction.
Digital rights management includes a function of managing rights given to each of the apparatuses of the home network and a function of managing rights given to contents which are reproducible on the home network. Digital rights management is performed by application programs installed in the apparatuses of the home network. Recently, several digital rights management application programs, such as SmartRight developed by Thompson, Open Conditional Content Access Management (OCCAM) developed by Cisco, xCP Cluster Protocol developed by IBM, and Digital Transmission Content Protection (DTCP) developed by Digital Transmission License Administration (DTLA), have been suggested.
In a typical digital rights management system, devices constituting a home network are classified into a master device and slave devices. The master device assigns rights to other devices, changes or nullifies the rights given to the other devices, sets rights in content in the home network, or changes or nullifies the rights set in the content. The slave devices are further classified into a media renderer and a media source. The media renderer decodes and then reproduces content. The media source provides the content to the media renderer. Whether a device in the home network is a master device or a slave device is determined depending on the particular functions a digital rights management application program serves.
In a recent home network system, a master device and a slave device communicate with each other by using universal plug and play (uPnP) protocol. The uPnP protocol is a technology that automatically qualifies a device for or disqualifies the device from membership of a home network by automatically recognizing the device and whether or not the device is currently connected to the home network.
FIG. 1 is a diagram illustrating an uPnP protocol-based home network. Referring to FIG. 1, the uPnP protocol-based home network comprises control devices (CDs) 20, 30, and 40 and a control point (CP) 10.
The CP 10 searches the uPnP protocol-based home network for the CDs 20 through 40 and recognizes whether each of the CDs 20 through 40 is newly connected to the uPnP protocol-based home network by receiving an advertisement message from the corresponding CD. The advertisement message is generated when each of the CDs 20 through 40 is newly connected to or disconnected from the uPnP protocol-based home network. The CP 10 receives a description message from each of the CDs 20 through 40. Also, the CP 10 transmits and receives event messages associated with actions involving each of the CDs 20 through 40. Each action involving the CP 10 and each of the CDs 20 through 40 is defined by a markup language, for example, XML.
Each of the CDs 20 through 40 transmits an advertisement message to the CP 10 whenever it is connected to or disconnected from the uPnP protocol-based home network. Further, each of the CDs 20 through 40 periodically transmits a message to the CP 10 in order to confirm whether it still exists on the uPnP protocol-based home network. In addition, each of the CDs 20 through 40 responds to various requests issued by the CP 10 according to the uPnP protocol. Each of the CDs 20 through 40 may be either a media source or a media renderer. In FIG. 1, elements 12, 14, and 16 denote the transmissions of messages between the CP 10 and the CD 20, between the CP 10 and the CD 30, and between the CP 10 and the CD 40, respectively, and elements 22 and 32 denote the transmissions of contents between the CD 20 and the CD 30 and between the CD 30 and the CD 40, respectively.
As described above, each of the CDs 20 through 40 may be a media renderer, which reproduces content, or a media source, which provides the content to the media renderer. The media renderer generally has a recording function so that it can store content received from the media source in its recording medium. The media source may be a contents database or contents broadcast.
In a case where the media source broadcasts media content to the media renderer, the media renderer has two recording functions, i.e., a real-time recording function, which enables a user to manually record content when the content is broadcasted, and a scheduled recording function, which schedules recording of content to be broadcasted in the near future so that the content can be automatically recorded at scheduled recording time.
According to the manual and scheduled recording functions, it is determined whether to record content by determining whether the content is recordable based on copy control information defined in the content. The copy control information can be defined in various manners depending on which digital rights management a home network employs. One type of copy control information is “copy never”, which only allows content to be reproduced by a media renderer and prevents the content from being copied to a recording medium in the media renderer.
FIG. 2 is a flowchart of a conventional scheduled recording method. Referring to FIG. 2, in operation 210, a user inputs scheduled recording information and a command to scheduled-record content to a CP. The CP may be a device having a user interface, such as a personal digital assistant (PDA), a personal computer, or a remote control device. The scheduled recording information is information necessary for scheduled-recording the content and includes scheduled recording start time, scheduled recording date, running time of the content, a channel, at which the content is to be broadcasted, the title of the content, and a recording type.
In operation 212, the CP transmits the scheduled recording information and the command to scheduled-record the content to a recording device, i.e., a CD (control device). The recording medium is a media renderer in a home network, which reproduces media content or stores the media content in its recording medium.
In operation 214, the CD determines whether the content has copy control information
In operation 220, if the content has the copy control information, the method proceeds to operation 230, and otherwise, the method proceeds to operation 240.
In operation 240, the CD transmits a message indicating that the content is recordable to the CP, which may then inform the user. In general, the copy control information is periodically updated. Thus, the copy control information may not exist in the CD at the time when the CP transmits the command to schedule-record the content to the CD. It is impossible to determine whether the content is recordable if the copy control information does not exist in the CD. However, the CD transmits the message indicating that the content is recordable to the CD regardless of whether the content has the copy control information.
In general, the copy control information is included in an electronic program guide (EPG), and the EPG is updated every few hours or every few days. The EPG is provided by a media source.
In operation 242, a scheduled recordings list is formed based on the scheduled recording information of the content. The scheduled recordings list identifies the content, which is scheduled to be scheduled-recorded, and includes various information necessary for scheduled-recording the content, such as scheduled recording time.
In operation 244, the CD checks the copy control information of the content when the scheduled recording time has arrived. At the moment when the content is broadcasted, the copy control information of the content must exist in the CD.
In operation 246, if the copy control information of the content is “copy never”, the method proceeds to operation 248, and otherwise, the method proceeds to operation 238.
In operation 248, if the copy control information of the content is “copy never”, the CD transmits an error message indicating that the content cannot be recorded to the CP to notify the user, and the method is completed.
In operation 238, if the copy control information of the content is not “copy never”, the content is recorded at the scheduled recording time according to the scheduled recordings list formed in operation 242.
If the content is determined to have the copy control information in operation 220, the method proceeds to operation 230. In operation 230, it is determined whether the content is recordable based on the copy control information. Thereafter, depending on whether the copy control information of the content is “copy never”, the method may proceed to operation 232 or 234.
More specifically, if the copy control information of the content is “copy never”, the CD transmits the error message to the CP, which may notify the user, in operation 232.
Otherwise, the CD transmits an OK message indicating that the content is recordable to the user in operation 234, forms a scheduled recordings list in operation 236, and records the content at the scheduled recording time according to the scheduled recordings list in operation 238.
According to the conventional method of scheduled-recording content, if copy control information of content of interest does not exist in a CD at any given moment or if the copy control information of the content of interest is “copy never”, a user cannot realize that the content of interest is not recordable until scheduled recording time of the content of interest because he/she only can check the copy control information of the content of interest and then realize that the copy control information of the content of interest is “copy never” after the scheduled recording time of the content of interest.
Therefore, the user may not have much time to come up with how to deal with a failure to scheduled-record the content of interest and cannot take appropriate measures to obtain the content of interest on time.